The invention relates to a method and a system for sending a radio paging message to radiotelephone subscriber stations of mobile radiotelephone subscribers of a cellularly constructed mobile radiotelephone network.
In cellular mobile radiotelephone networks, the location of radiotelephone subscriber stations of the mobile radiotelephone subscribers are managed on the basis of location areas (location areas) that are respectively assembled from one or several radio cells and that can be identified by means of an associated location area identifier (location area identity). From the system specification “D900 Mobile Communication System,” by Huder/Geier, Siemens AG 1992 (order number A30808-X3231-X-2-7618), a cellularly constructed digital mobile radiotelephone network is known that is operated according to the GSM standard (Global System for Mobile Communication). In the case of the setup of a connection to the radiotelephone subscriber stations, e.g. on the basis of a call initiated from another network and directed to the mobile radiotelephone subscriber (mobile terminated call), a radio paging message is transmitted into all radio cells of the location area in which the called mobile radiotelephone subscriber is located with his radiotelephone subscriber station (paging). The radio paging message serves to prompt the mobile radiotelephone subscriber to register himself with his radiotelephone subscriber station in the network, or, respectively, at the installations thereof—the responsible base transceiver station. Due to the fact that the radio paging message must always be transmitted to all the radio cells of the known location area, a high load arises both for the concerned installations of the mobile radiotelephone network that are involved in the signaling and also for the signaling channels in the radio cells. In the radio cells, the paging message is sent on control channels. The signaling load increases proportionally given an increasing number of radio cells in a location area.
From the international patent application WO93/23965, a cellular communication system is known in which a radio paging message can be transmitted to radiotelephone subscriber stations within a service area (service area) (paging). Paging regions are thereby defined that consist of a multiplicity of location areas (location areas). The paging message is first transmitted to the location area, and is subsequently transmitted into the larger paging area for the case in which the radio paging message remains unanswered. An item of information for the identification of the current location area is transmitted to the communication system by each radiotelephone subscriber station.
From the international patent application WO94/07337, a cellular mobile radiotelephone network is known in which a subscriber-specific and temporary paging area is defined for a radiotelephone subscriber station that is moving in a particular cell of a paging area consisting of one or several radio cells. A timer thereby starts for the selected radiotelephone subscriber station as soon as it goes into the paging area, and an initialization message is activated after the elapsing of a predeterminable time duration. This message causes the network to define the temporary paging area and to store it in a subscriber database of the network. The smallest paging area comprises only a single radio cell.